UserActivityID auto_increment

Question

我在将值从java插入到mysql时遇到了问题，它仍然让我对如何插入自动增量感到困惑--有些人说，如果不插入值，它将是自动的。此外，我还尝试使用add set Int(1，null)和错误。

public void mase(){

   String time=dateFormat.format(date);

   String SQLTIME="INSERT INTO history (UserActivityID, UserTimeActivity, UserActivity) VALUES (null,?,?)";

try {
    JOptionPane.showMessageDialog(this, "?");

    Connection con=DriverManager.getConnection("jdbc:mysql://localhost:3306/atm?zeroDateTimeBehavior=convertToNull", "root", "");
    PreparedStatement prstm=con.prepareStatement(SQLTIME);
    prstm = con.prepareStatement(SQLTIME,PreparedStatement.RETURN_GENERATED_KEYS);

    prstm.setString(1, time);
    prstm.setString(2,"Cash Withdraw");
    int rowsInserted = prstm.executeUpdate();
    if (rowsInserted > 0) {

     JOptionPane.showMessageDialog(this," inserted successfully!");
     }

} catch (SQLException | HeadlessException | ClassCastException ex) {
    JOptionPane.showMessageDialog(this, ex); 
}
    JOptionPane.showMessageDialog(this, time); 

}

Answer 1

从命令中排除UserActivityID，DB管理器将为您插入它。

String SQLTIME="INSERT INTO history (UserTimeActivity, UserActivity) VALUES (?,?)"；